US10928610B2ActiveUtilityA1

Photographing system, image capturing unit and electronic device

98
Assignee: LARGAN PRECISION CO LTDPriority: Feb 17, 2015Filed: Apr 13, 2020Granted: Feb 23, 2021
Est. expiryFeb 17, 2035(~8.6 yrs left)· nominal 20-yr term from priority
Inventors:Wei-Yu Chen
G02B 13/18G02B 5/005G02B 13/0045G02B 27/0025G02B 13/002G02B 9/64
98
PatentIndex Score
5
Cited by
29
References
25
Claims

Abstract

A photographing system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element with refractive power. The first lens element with positive refractive power has an object-side surface being convex in paraxial region. The second lens element with refractive power has an image-side surface being concave in paraxial region. The third, fourth and fifth lens elements all have refractive powers. The sixth lens element with refractive power has an image-side surface being concave in paraxial region, wherein the image-side surface has at least one convex shape in off-axis region, and both of two surfaces are aspheric. The seventh lens element with refractive power has an object-side surface being concave in paraxial region, and both of two surfaces are aspheric.

Claims

exact text as granted — not AI-modified
What is claimed is: 
     
       1. A photographing system comprising seven lens elements, the seven lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element;
 wherein the second lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof, the third lens element has positive refractive power, the seventh lens element with negative refractive power has an image-side surface being concave in a paraxial region thereof, the image-side surface of the seventh lens element has at least one convex critical point in an off-axis region thereof, and an object-side surface and the image-side surface of the seventh lens element are both aspheric; 
 wherein a central thickness of the third lens element is larger than a central thickness of the fourth lens element. 
 
     
     
       2. The photographing system of  claim 1 , wherein the fourth lens element has an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof. 
     
     
       3. The photographing system of  claim 1 , wherein the fifth lens element has an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof. 
     
     
       4. The photographing system of  claim 1 , wherein a focal length of the photographing system is f, a composite focal length of the third lens element, the fourth lens element and the fifth lens element is f345, and the following condition is satisfied:
   −0.30< f/f 345<0.60.
 
 
     
     
       5. The photographing system of  claim 1 , wherein the sixth lens element has an object-side surface being convex in a paraxial region thereof, and the object-side surface of the sixth lens element has at least one concave shape in an off-axis region thereof. 
     
     
       6. The photographing system of  claim 1 , wherein an f-number of the photographing system is Fno, and the following condition is satisfied:
     F no≤2.25.
 
 
     
     
       7. The photographing system of  claim 1 , wherein an axial distance between an object-side surface of the first lens element and an image-side surface of the fourth lens element is Dr1r8, an axial distance between an object-side surface of the fifth lens element and the image-side surface of the seventh lens element is Dr9r14, and the following condition is satisfied:
   0.75< Dr 1 r 8/ Dr 9 r 14<1.5. 
 
     
     
       8. The photographing system of  claim 1 , wherein the third lens element has an object-side surface being convex in a paraxial region thereof, and the object-side surface of the third lens element has at least one concave shape in an off-axis region thereof. 
     
     
       9. The photographing system of  claim 1 , wherein a focal length of the photographing system is f, a curvature radius of an image-side surface of the sixth lens element is R12, a curvature radius of the object-side surface of the seventh lens element is R13, and the following condition is satisfied:
   0.30<( f/R 12)−( f/R 13).
 
 
     
     
       10. The photographing system of  claim 1 , wherein the sixth lens element has positive refractive power. 
     
     
       11. The photographing system of  claim 1 , wherein the sixth lens element has an image-side surface being concave in a paraxial region thereof, and the image-side surface of the sixth lens element has at least one convex shape in an off-axis region thereof. 
     
     
       12. The photographing system of  claim 1 , wherein a projection of a position of a maximum effective radius of the image-side surface of the seventh lens element on an optical axis is closer to the object side of the photographing system than an intersection of the object-side surface of the seventh lens element and the optical axis. 
     
     
       13. An image capturing unit, comprising:
 the photographing system of  claim 1 ; and 
 an image sensor disposed on an image surface of the photographing system. 
 
     
     
       14. An electronic device, comprising:
 the image capturing unit of  claim 13 . 
 
     
     
       15. A photographing system comprising seven lens elements, the seven lens elements being, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element;
 wherein the second lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof, the third lens element with positive refractive power has an image-side surface being convex in a paraxial region thereof, the fourth lens element has negative refractive power, the seventh lens element has an image-side surface being concave in a paraxial region thereof, the image-side surface of the seventh lens element has at least one convex critical point in an off-axis region thereof, and an object-side surface and the image-side surface of the seventh lens element are both aspheric; 
 wherein an f-number of the photographing system is Fno, and the following condition is satisfied:
     F no≤2.25.
 
 
 
     
     
       16. The photographing system of  claim 15 , wherein the fourth lens element has an object-side surface being concave in a paraxial region thereof and an image-side surface being convex in a paraxial region thereof. 
     
     
       17. The photographing system of  claim 15 , wherein a sum of axial distances between every adjacent lens element of the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element, the sixth lens element and the seventh lens element is ΣAT, an axial distance between the third lens element and the fourth lens element is T34, an axial distance between the fourth lens element and the fifth lens element is T45, and the following condition is satisfied:
   3.0<Σ AT /( T 34+ T 45)<10.0.
 
 
     
     
       18. The photographing system of  claim 15 , wherein an axial distance between an object-side surface of the first lens element and an image-side surface of the fourth lens element is Dr1r8, an axial distance between an object-side surface of the fifth lens element and the image-side surface of the seventh lens element is Dr9r14, and the following condition is satisfied:
   0.75< Dr 1 r 8/ Dr 9 r 14<1.5. 
 
     
     
       19. The photographing system of  claim 15 , wherein a focal length of the photographing system is f, a composite focal length of the third lens element, the fourth lens element and the fifth lens element is f345, and the following condition is satisfied:
   −0.30< f/f 345<0.60.
 
 
     
     
       20. The photographing system of  claim 15 , wherein the sixth lens element with positive refractive power has an object-side surface being convex in a paraxial region thereof, and the object-side surface of the sixth lens element has at least one concave shape in an off-axis region thereof. 
     
     
       21. The photographing system of  claim 15 , wherein a projection of a position of a maximum effective radius of the image-side surface of the seventh lens element on an optical axis is closer to the object side of the photographing system than an intersection of the object-side surface of the seventh lens element and the optical axis. 
     
     
       22. The photographing system of  claim 15 , wherein a focal length of the photographing system is f, a curvature radius of an image-side surface of the sixth lens element is R12, a curvature radius of the object-side surface of the seventh lens element is R13, and the following condition is satisfied:
   0.30<( f/R 12)−( f/R 13).
 
 
     
     
       23. The photographing system of  claim 15 , wherein the second lens element has an image-side surface being concave in a paraxial region thereof. 
     
     
       24. An image capturing unit, comprising:
 the photographing system of  claim 15 ; and 
 an image sensor disposed on an image surface of the photographing system. 
 
     
     
       25. An electronic device, comprising:
 the image capturing unit of  claim 24 .

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